阅读说明：本技术 光电子设备和激光雷达系统 (Optoelectronic device and lidar system ) 是由 胡贝特·哈尔布里特 拉尔夫·维尔特 彼得·布里克 于 2020-03-17 设计创作，主要内容包括：一种光电子设备,尤其用于检测障碍物和/或用于距离测量,包括：用于发出激光束的发送装置(21),其中发送装置(21)具有像素(25)的场(23),其中像素场(23)的每个像素(25)具有至少一个激光器,尤其是光电子激光器,例如VCSEL,其中像素场(23)的像素(25)划分成多个像素组,并且其中发送装置(21)构成用于,在不同的相继的时间间隔内运行像素组。(Optoelectronic device, in particular for detecting obstacles and/or for distance measurement, comprising: transmitting device (21) for emitting a laser beam, wherein the transmitting device (21) has a field (23) of pixels (25), wherein each pixel (25) of the field (23) of pixels has at least one laser, in particular an optoelectronic laser, for example a VCSEL, wherein the pixels (25) of the field (23) of pixels are divided into a plurality of pixel groups, and wherein the transmitting device (21) is designed to operate the pixel groups in different successive time intervals.)

1. Optoelectronic device, in particular for detecting obstacles and/or for distance measurement, having:

transmitting device (21) for emitting a laser beam, wherein the transmitting device (21) has a field (23) of pixels (25), wherein each pixel (25) of the pixel field (23) has at least one laser, in particular an optoelectronic laser, such as a VCSEL, μ VCSEL, VECSEL or μ VECSEL,

wherein the pixels (25) of the pixel field (23) are divided into a plurality of pixel groups, and

wherein the transmission device (21) is designed to operate the pixel groups in different successive time intervals.

2. An optoelectronic device as claimed in claim 1,

it is characterized in that the preparation method is characterized in that,

the pixel groups can be run in varying order within the time interval.

3. An optoelectronic device according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the pixel field (23) is divided into a number N of segments (27), wherein in each segment (27) a respective pixel (25) is associated with a respective pixel group.

4. An optoelectronic device according to claim 3,

it is characterized in that the preparation method is characterized in that,

each section (27) has the same number L of pixels (25), and/or

There are a number K of pixel groups (25),

wherein for each section (27) the number K of pixel groups (25) corresponds to a number L of pixels (25).

5. Optoelectronic device according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the optoelectronic device has a receiving device (33) for detecting a laser beam, in particular a laser beam reflected back at the object,

wherein the receiving device (33) preferably has a two-dimensional detection field (35) which is divided into a number M of detection regions (37), wherein each detection region (37) forms a laser beam for detecting the transmitting device (21).

6. The optoelectronic device of claim 5,

it is characterized in that the preparation method is characterized in that,

the M number of detection regions (37) corresponds to the N number of segments (27), into which the pixel field (23) is divided, wherein in each case one detection region (37) is associated with in each case one segment (27), such that the detection regions (37) are provided for detecting the reflected laser beam originating from the associated segment (27).

7. The optoelectronic device according to claim 5 or 6,

it is characterized in that the preparation method is characterized in that,

each detection area (37) has at least one pixel (25) for detecting laser radiation.

8. The optoelectronic device according to any one of claims 3 to 7,

it is characterized in that the preparation method is characterized in that,

all pixels (25) of the same section (27) of the pixel field (23) emit laser beams having the same polarization and/or the same wavelength.

9. Optoelectronic device according to one of claims 3 to 8,

it is characterized in that the preparation method is characterized in that,

the pixels (25) of at least one first section (27a, 27d) of the pixel field (23) emit a laser beam having a first polarization (H),

the pixels of at least one second segment (27b, 27c) of the pixel field (23) emit a laser beam having a second polarization (V),

wherein the first and second polarizations are different and in particular orthogonal to each other.

10. Optoelectronic device according to one of claims 3 to 9,

it is characterized in that the preparation method is characterized in that,

the pixels (25) of at least one first section (27a, 27d) of the pixel field (23) emit a laser beam having a first wavelength,

the pixels (25) of at least one second section (27d, 27c) of the pixel field (23) emit a laser beam having a second wavelength,

wherein the first wavelength is different from the second wavelength.

11. Optoelectronic device according to one of claims 3 to 10,

it is characterized in that the preparation method is characterized in that,

the segments (27) of the pixel field (23) form at least two rows, wherein each row has at least two pixels (25).

12. The optoelectronic device of claim 11,

it is characterized in that the preparation method is characterized in that,

the pixels (25) of a first segment (27a, 27d) of the pixel field (23) emit a laser beam having a polarization (H) which is different from a polarization (V) of the laser beam emitted by the pixels (25) of at least one second segment (27b, 27c), wherein the second segments (27b, 27c) are arranged adjacent to the first segments (27a, 27d) in the same or in a next row.

13. The optoelectronic device according to claim 11 or 12,

it is characterized in that the preparation method is characterized in that,

the pixels (25) of a first section (27a, 27d) of the pixel field (23) emit a laser beam having a wavelength which is different from the wavelength of the laser beam emitted by the pixels (25) of at least one second section (27b, 27c), wherein the second section (27b, 27c) is arranged adjacent to the first section (27a, 27b) in the same or a next row.

14. Optoelectronic device according to one of claims 5 to 13,

it is characterized in that the preparation method is characterized in that,

each detection area (37a-37d) has at least one polarization filter that matches the polarization (V, H) of the laser radiation emitted by the pixels of the associated segment (27a-27 d).

15. Optoelectronic device according to one of claims 5 to 14,

it is characterized in that the preparation method is characterized in that,

each detection area (37a-37d) has at least one spectral filter that matches the wavelength of the laser radiation emitted by the pixels (25) of the associated segment (27a-27 d).

16. Optoelectronic device according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

at least one pixel (25) and preferably each pixel (25) has at least two lasers (43a, 43b) having different temperature operating ranges,

wherein preferably the temperature operating range of at least one of the lasers (43a) of the pixel (25) is in a first interval, in particular in the range of-40 ℃ to +40 ℃, and

wherein it is furthermore preferred that the temperature operating range of the at least one further laser (43b) of the pixel (25) is within a second interval, in particular within the range of +40 ℃ to +120 ℃.

17. The optoelectronic device of claim 16,

it is characterized in that the preparation method is characterized in that,

at least two lasers (43a, 43b) of a pixel (25) can be operated together, or

At least one laser (43a, 43b) is operable in dependence on a current temperature, which lies within a temperature operating range of the at least one laser.

18. An optoelectronic device according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

at least one first pixel has only two or more lasers (43a) having a first temperature operating range and at least one second pixel has only two or more lasers (43b) having a second temperature operating range.

19. Optoelectronic device, in particular for detecting obstacles and/or for distance measurement, having:

transmitting device (21) for emitting a laser beam, wherein the transmitting device (21) has a field (23) of pixels (25), wherein each pixel (25) of the pixel field (23) has at least one laser, in particular an optoelectronic laser, for example a VCSEL or VECSEL, and

receiving means (33) for detecting a laser beam, in particular a laser beam reflected back at the object,

wherein the pixels (25) of the pixel field (23) are divided into a plurality of pixel groups, and

wherein the transmission device (21) is designed to operate the pixel groups in different successive time intervals.

20. An optoelectronic device, in particular for detecting obstacles and/or for distance measurement,

optoelectronic device, in particular according to any of the preceding claims,

wherein the optoelectronic device comprises:

transmitting device (21) for emitting a laser beam, wherein the transmitting device (21) has a field (23) of pixels (25), wherein each pixel (25) of the pixel field (23) has at least one laser, in particular an optoelectronic laser, for example a VCSEL, a μ VCSEL, a VECSEL or a μ VECSEL,

wherein the pixels (25) of the pixel field (23) are divided into at least a first pixel group (67) and a second pixel group (69),

wherein each pixel (25) of the first pixel group (67) has at least one optoelectronic laser which is designed for laser operation in a first temperature range, for example between-40 ℃ and +25 ℃, and

wherein each pixel (25) of the second pixel group (69) has at least one optoelectronic laser which is designed for laser operation in a second temperature range, for example between 25 ℃ and +90 ℃.

21. The optoelectronic device of claim 20,

it is characterized in that the preparation method is characterized in that,

the respective optoelectronic laser has a resonator device and an active region, wherein the active region is embedded in the resonator device.

22. The optoelectronic device of claim 21,

it is characterized in that the preparation method is characterized in that,

the resonator arrangements of the optoelectronic lasers of the first pixel group (67) and the resonator arrangements of the optoelectronic lasers of the second pixel group (69) are at least substantially identically formed and/or at least substantially identically dimensioned.

23. The optoelectronic device according to claim 21 or 22,

it is characterized in that the preparation method is characterized in that,

the active regions of the optoelectronic lasers of the first pixel group (67) and the active regions of the optoelectronic lasers of the second pixel group (69) are configured and/or dimensioned differently,

wherein the active region of the optoelectronic laser of the first pixel group (67) is coordinated with the laser operation in the first temperature range, and

wherein the active region of the optoelectronic laser of the second pixel group (69) is coordinated with the laser operation in a second temperature range.

24. The optoelectronic device of any one of claims 21 to 23,

it is characterized in that the preparation method is characterized in that,

the optoelectronic lasers of the first group of pixels (67) originate from a first wafer and the optoelectronic lasers of the second group of pixels (69) originate from a second wafer.

25. The optoelectronic device of any one of claims 20 to 24,

it is characterized in that the preparation method is characterized in that,

the pixel field (23) comprises a plurality of rows or columns of pixels (25),

wherein only pixels of the first pixel group (67) or pixels of the second pixel group (69) are arranged alternately in successive rows or columns, respectively, or

Wherein the pixels (25) of the first and second pixel groups (67, 69) are arranged alternately in each row or in each column, in particular such that a checkerboard arrangement of the pixels (25) of the first and second pixel groups (67, 69) is formed.

26. The optoelectronic device of any one of claims 20 to 25,

it is characterized in that the preparation method is characterized in that,

the optoelectronic lasers of the first pixel group (67) can be electrically actuated separately from the optoelectronic lasers of the second pixel group (69).

27. A lidar system having:

at least one optoelectronic device according to any one of the preceding claims, and

evaluation means for determining the distance to an object reflecting the emitted laser beam on the basis of the laser beam detected by means of the receiving means (33) of the optoelectronic device.

28. A method for manufacturing an optoelectronic device, in particular according to any one of claims 1 to 26, wherein the method comprises the steps of:

a pixel field (23) having a plurality of pixels (25) is formed on a carrier (53), wherein each pixel (25) has at least one optoelectronic laser, in particular a VCSEL or a μ VCSEL, and

at least one electronic controller (57) for actuating the pixels (25) is provided, in particular on a carrier (53), wherein the pixels (25) of the pixel field (23) are divided into a plurality of pixel groups (25) for actuating purposes, and wherein the controller is designed such that the controller operates the pixels (25) of the groups in different successive time intervals.

Technical Field

The present patent application claims priority from german application DE 102019107957.8, 3, 27, 2019, the disclosure of which is incorporated herein by reference.

The invention relates to an optoelectronic device, in particular for detecting obstacles and/or for distance measurement, and to a lidar system.

Background

Lidar (laser radar) is an abbreviation for "Light Detection and Ranging", and the Lidar system is also known as the Ladar system. Herein, Ladar stands for "Laser Detection and Ranging". The Lidar system, also referred to below as a Lidar sensor system, works similarly to radar systems and is used, for example, for optical distance and velocity measurements and also, in addition, for measuring atmospheric parameters or for creating an altitude profile of the earth's surface. Unlike a radar system using radio waves, a Lidar system uses laser radiation.

The data sets generated by the LIDAR sensor system may be used for control and steering of vehicles (e.g., automobiles, ships, airplanes, drones), including vehicles with driver assistance systems, as well as semi-automatic or fully automatic vehicles. Furthermore, LIDAR systems may also be used for many different functions for the interior space of a vehicle. Such functions may include driver or passenger monitoring functions as well as occupancy detection systems, e.g. based on eye tracking, face recognition (evaluation of head rotation or tilt), blink measurements, etc. Thus, the LIDAR sensor system may be mounted not only outside but also inside the vehicle, and may be integrated into optical systems, such as headlamps and other vehicle lighting components located at different locations on the vehicle (front, rear, sides, corners, interior space).

Thus, light sources for LIDAR applications provide electromagnetic radiation by means of which information about objects in the surroundings of the LIDAR system is determined. Common LIDAR light sources used in the prior art emit radiation in the invisible wavelength range, in particular Infrared Radiation (IR) in the wavelength range of 850nm to 8100 nm. The light source preferably emits radiation within a narrow bandwidth range having a full width at half maximum (FWHM) between 1ns and 100 ns.

A LIDAR sensor system is a system that uses light or electromagnetic radiation to derive information about objects in the surroundings of the LIDAR system. LIDAR sensor systems typically include a number of components as described below. In an exemplary application, such LIDAR systems are disposed on vehicles in order to derive information about objects on and near streets. These objects may include other traffic participants (e.g., vehicles, pedestrians, riders, etc.), elements of road infrastructure (e.g., traffic signs, traffic lights, lane markers, crash barriers, islands, sidewalks, piers, etc.), and also objects that are discovered intentionally or unintentionally on or near streets.

Information derived via such LIDAR sensor systems may include distances, velocities, accelerations, directions of motion, flight paths, attitudes, and/or other physical or chemical characteristics of such objects. To derive this information, after radiation emitted by at least one object is reflected or scattered in an Illumination Field (also referred to herein as an object Field) and detected by a detector, the LIDAR system may determine changes in Time of Flight (TOF) or physical characteristics, such as phase, amplitude, frequency, polarization, structured dot pattern, triangulation methods, etc., of the emitted electromagnetic radiation.

Lidar systems known from the prior art use mechanical and non-mechanical scanning systems. Mechanical solutions may include rotating mirrors, oscillating mirrors, especially oscillating microelectromechanical mirrors (MEMS), Digital Mirror Devices (DMD), galvanometer scanners (Galvo-Scanner), fiber-based scanning systems, and the like. The movable mirror may have a flat surface area, such as an oval, rectangular, or polygonal shape, and may tilt or pivot about one or more axes. Non-mechanical solutions may include so-called Optical Phased Arrays (OPAs), where the phase of the light wave is changed by dynamically controlling the optical properties of settable optical elements, such as phase modulators, phase shifters, liquid crystal elements (LCDs) etc. In each of these cases, the radiation reflected back can be detected by means of a single detector. Lasers used as light sources, as well as movable mirrors and other scanning or flashing systems described above, are relatively expensive.

Other lidar systems known in the art allow simultaneous illumination of a target area. Here, the laser beam reflected back from the entire target area, also referred to as field of view (FoV), is detected by means of a high resolution detector system, also referred to below as a camera. The detected camera image provides here position information of the target area. Such a camera or detection system is relatively expensive due to the high resolution required.

A detector is a device capable of providing (to an evaluation electronics unit) an output signal that is qualitatively or quantitatively related to the presence or change of a physical (or chemical) property in its surroundings. Examples of such physical properties are temperature, pressure, acceleration, brightness of light (UV, VIS, IR), vibration, electric field, magnetic field, electromagnetic field, acoustic or ultrasonic waves, etc. The detector means may comprise a camera (monochrome or stereo) such as a CCD or CMOS chip or a stacked multi-layer photodiode with a light sensitivity, a detector of radio waves (radar system), a photodiode, a temperature sensor such as an NTC element, i.e. a thermistor with a negative temperature coefficient, an acceleration sensor, etc.

A photodetector is a detection device that is sensitive to the effects of electromagnetic radiation. Typically, photons are converted into current signals when they impinge on the light sensitive element. The photosensitive element may comprise a semiconductor element having a pn junction region in which photons are absorbed and converted into electron-hole pairs. Many different detector types may be used for LIDAR applications, such as photodiodes, PN diodes, PIN diodes (positive intrinsic negative diodes), APDs (avalanche photodiodes), SPADs (single photon avalanche diodes), sipms (silicon photomultipliers), CMOS sensors (complementary metal oxide semiconductors, CCDs (Charge-Coupled devices)), stacked multilayer photodiodes, etc.

In LIDAR systems, a photodetector may be used to detect (qualitatively and/or quantitatively) the echo signals of light that is emitted by a light source in the field of view (FoV) and that is subsequently reflected or scattered by at least one object within the field of view (FoV). The photodetector may comprise one or more light sensitive elements (of the same type or of different types), which may be arranged in a linear strip or in a two-dimensional array. The photosensitive region may be rectangular, square, polygonal, circular or elliptical in shape. The photodetectors may be covered with bayer-like visible light or infrared filter segments.

Disclosure of Invention

The invention is based on the object of providing an optoelectronic device which can be realized relatively simply and at low cost and which is particularly suitable for use in a lidar system.

This object is achieved by an optoelectronic device having the features of claim 1. Preferred embodiments and further developments of the invention are specified in the dependent claims.

The optoelectronic device according to the invention, which is suitable in particular for detecting obstacles and/or distance measurements, for example in a Laser radar system, comprises a transmitter for Emitting a Laser beam, wherein the transmitter has a pixel field, wherein each pixel of the pixel field has at least one Laser, in particular an optoelectronic Laser, for example a Surface-Emitting Semiconductor Laser with a VCSEL (Vertical-Cavity Surface-Emitting Laser) or a VECSEL (Surface-Emitting Semiconductor Laser with an external Laser Resonator). The optoelectronic device according to the invention optionally also comprises a receiving device for detecting the laser beam, in particular the laser beam reflected back on the object. In the optoelectronic device according to the invention, the pixels of the pixel field are divided into a plurality of pixel groups, and the transmission device is designed to operate the pixel groups in different, successive time intervals.

The optoelectronic device therefore comprises a pixelated transmitting means for emitting the laser beam. Here, for example, a pixel field may have 600 × 200 pixels. Each pixel may have one or more VCSELs, for example. Here, each pixel is associated with one of a plurality of pixel groups. The pixels in a pixel group are operated for a short time, i.e. are switched on for a particularly short time, and then switched off again. Here, the pixels of the other pixel group are not operated. The pixel groups are operated in succession in successive time intervals, which may be, for example, one microsecond in length in each case. The time specification of 1 mus is only to be considered as an example. Other time intervals are also possible. For example, the time interval may be in a range between 1 μ s and 3 μ s, inclusive.

Thereby, the transmitting device allows the target area to be irradiated simultaneously via the laser light from the respective pixels operating within the time interval. Since not all pixels of the pixel field are operated simultaneously, but only the pixels associated with the respective pixel group are operated within a time interval, a high-resolution receiving device is not required for detecting the reflected laser beam, but a receiving device with a relatively coarse resolution suffices, as will be explained in more detail below. The costs for the receiving device and thus also the optoelectronic device can be reduced thereby.

Lidar systems known in the art that use a movable mirror to scan a target area with a collimated laser beam typically require a laser that operates at relatively high currents, for example in the range between 30A and 40A. The laser pulses generated here can have a peak power of 100W or more. Due to the high currents used for operating such lasers, it is problematic in the known lidar systems to generate laser pulses shorter than a few nanoseconds. The maximum pulse power of the laser pulse is usually limited because the energy of the laser pulse affects eye safety.

In the transmitting device of the optoelectronic device according to the invention, a pixel or a group of a plurality of pixels can be manipulated individually. The current required for this is usually one tenth of the current mentioned above. The pixels are thus for example in the range of a few amperes. Laser pulses shorter than one nanosecond can thereby be generated. The pulse energy of the laser pulses can thereby be reduced, thereby improving eye safety.

Furthermore, a distribution of the laser radiation is formed in the target region or in a spatial region between the transmitting device and the irradiated target region. As a result, a lower power density of the emitted laser radiation is formed, which in turn has a favorable effect on eye safety.

Lidar systems known in the art use movable mirrors to scan a target area with a collimated laser beam-if the lidar system is used in a motor vehicle-typically only put into operation when the vehicle exceeds a certain speed. The reason for this is to ensure eye safety of, for example, passers-by. Since the optoelectronic device according to the invention offers improved eye safety, it is possible to put the optoelectronic device into operation at low speeds when used in a lidar system in the case of a motor vehicle.

In lidar systems known from the prior art that use movable mirrors, the mirrors typically oscillate or rotate at a resonant frequency. The light pulse can therefore only be emitted within a specific angular range at specific, periodically repeating points in time. This means, for example, that in the case of two vehicles each using a lidar system being close to each other, no one-to-one correspondence or no distinction can be established between external lidar pulses and lidar pulses reflected on objects originating from the own vehicle, since, as stated, it is still unclear: from which vehicle the laser pulse is emitted. This problem is known as "interference" (Jamming).

In one embodiment of the invention, it can be provided that the pixel groups are operated or operable in a varying sequence in different successive time intervals. Thus, the groups of pixels can be activated in an arbitrary order, in particular a random order, and thus carry random time stamps. The random time stamps may be generated using known mathematical or physical effects, e.g. based on a fibonacci sequence, e.g. based on thermal noise provided by the semiconductor device.

Thereby, correlations with laser radiation from other sources and/or periodicity of the emitted laser radiation may be avoided. The problem of "interference" no longer occurs, or at least occurs to a reduced extent. In one embodiment of the invention, the pixel field is divided into a number N of segments, wherein one or more pixels are each associated with a pixel group in each segment.

In one embodiment of the invention, the pixel field is divided into a number N of segments, wherein in each segment a pixel is associated with a pixel group. Thus, only one pixel is running in each section during each time interval. This allows the use of a receiving device with a relatively low resolution for detecting the laser beam, in particular reflected back. For example, cameras with a corresponding number N of sections may be used. Thus, the resolution of the camera may be defined by the number of segments N of the emitter. However, the camera's segmentation cannot correspond to the number of segments N of the pixel field either.

Each segment of the pixel field may have the same number L of pixels. The pixel field can thus be divided into N segments of the same size. This ensures that exactly one pixel is always associated with each pixel group in each section. Alternatively, the segments of the pixel field may be different in size. For example, a better resolution and thus a larger number of pixels can be provided in the middle section of the pixel field. Conversely, fewer pixels and consequently also a lower resolution may be provided at the edges of the pixel field.

There may be K number of pixel groups, where for each section, K number of pixel groups corresponds to L number of pixels. Thus, in each section, there may be associated with each pixel set from exactly one pixel. This is just one example. There may also be other relationships between the K number of pixel groups and the L number of pixels for each segment, for example K-1/2 or K-1/3.

The receiving means may have a two-dimensional detection field which is divided into a number M of detection areas, wherein each detection area constitutes a laser beam for detecting the transmitting means. The two-dimensional detection field may for example be an image sensor, such as a CCD sensor. CCD here represents a charge coupled device. By dividing the detection field into M detection regions, the detection field and thus the receiving means can have a relatively coarse resolution. This makes it possible to implement a low-cost embodiment. The number M of detection areas of the receiving device may correspond to the number N of segments into which the pixel field is divided.

It may be provided that one detection region each is associated with one segment each, so that a detection region is provided for detecting the reflected laser beam originating from the associated segment. Via a section of the pixel field, for example, a sub-region of the object field can be illuminated which precedes the receiving device at intervals, for example at intervals of 200 m. The irradiation of the subareas of the target field by means of the segment can be carried out via corresponding optical means. The laser beam reflected back by the subregions can likewise be deflected, for example, via suitable optical means, also referred to below as sensor optical means, onto the detection region associated with the segment. The target field can be irradiated in sections by means of a segmented pixel field, wherein the reflected laser beam from the irradiated segments of the target field can be detected via a detection field which is likewise divided into regions. The term "sensor optics" includes all types of optical elements that may be used in a LIDAR sensor system to ensure or improve its function. For example, such optical elements may include lenses or lens groups, filters, diffusers, mirrors, reflectors, photoconductors, Diffractive Optical Elements (DOEs), holographic optical elements, and generally all types of optical elements that may affect light or electromagnetic radiation via refraction, diffraction, reflection, transmission, absorption, scattering, or the like.

Each detection area may have at least one pixel for detecting laser radiation. The receiving means may thus have a relatively coarse resolution.

In one embodiment of the invention, all pixels of the same section of the pixel field emit laser beams having the same polarization and/or the same wavelength. In contrast, different segments of the pixel field may emit laser beams with different polarizations and/or different wavelengths and/or different powers. The detection of the reflected laser beam can thereby be improved. The pixels of the pixel field may also emit pulsed laser radiation in the form of individual pulses of the same pulse height or in the form of a plurality of pulse sequences with uniform pulse height or varying pulse height. The pulses may have a symmetrical pulse shape, such as a rectangular pulse shape. Alternatively, the pulses may be asymmetric pulse shapes, the respective rising and falling edges of which are different.

For example, it can be provided that the pixels of at least one first section of the pixel field emit laser beams with a first polarization, and the pixels of at least one second section of the pixel field emit laser beams with a second polarization, wherein the first polarization and the second polarization are different. If polarization-dependent detection is carried out in the detection region of the detection field of the receiving device, scattered light of the laser radiation from the first section can be avoided, for example, in the detection region associated with the second section of the pixel field.

It may be provided that the pixels of at least one first section of the pixel field emit a laser beam having a first wavelength, and the pixels of at least one second section of the pixel field emit a laser beam having a second wavelength, wherein the first wavelength and the second wavelength are different. In a manner corresponding to polarization-dependent detection, the proportion of scattered light in the detection region of the detection field of the receiving device can also be reduced if wavelength-dependent detection is carried out in the detection region. This can be done in particular by providing a spectral filter (for example an edge filter or a band-pass filter) upstream of each detection region, which spectral filter transmits light of a certain wavelength emitted by the section of the pixel field associated with the respective detection field, while the filter blocks other wavelengths.

The segments of the pixel field may form at least two rows, wherein each row comprises at least two pixels. Thus an array-like segmentation of the pixel field can be achieved.

The pixels of a first segment of the pixel field may emit a laser beam having a polarization that is different from the polarization of the laser beam emitted by the pixels of at least one second segment, wherein the second segment is arranged adjacent to the first segment in the same or a next row. Thus, segments of the pixel field which are adjacent to each other in a row or a column may emit laser beams with different polarizations.

The pixels of a first segment of the pixel field may emit a laser beam having a wavelength different from a wavelength of a laser beam emitted by pixels of at least one second segment, wherein the second segment is arranged adjacent to the first segment in the same or a next row. Therefore, sections of the pixel field adjacent to each other in a row or a column may emit laser beams having different wavelengths.

Each detection area may have a polarization filter that matches the polarization of the laser beam emitted by the pixels of the associated segment. The detection of scattered light can thereby be reduced.

In order to avoid the detection of scattered light, in particular solar background light, but also light from other lidar sources, it is also advantageous if each detection region has a spectral filter which is matched to the wavelength of the laser radiation emitted by the pixels of the associated segment.

In one embodiment of the invention, at least one pixel and preferably each pixel of the pixel field can have at least two lasers with different temperature operating ranges. Thus, the optoelectronic device can be adjusted in terms of the temperature operating range in which the optoelectronic device can be used. In this way, requirements such as those set forth in the manufacture of motor vehicles can be met in particular.

It is particularly advantageous in terms of automotive requirements that the temperature operating range of at least one laser of a pixel is within a first interval, for example within the range from-40 ℃ to +40 ℃, and the temperature operating range of at least one other laser of a pixel is within a second interval, for example within the range from +40 ℃ to +120 ℃. Thus, a temperature operating range of-40 ℃ to +120 ℃ as required in automobile manufacturing can be satisfied. The temperature operating range can also be divided into other intervals between-40 ℃ and 120 ℃.

In case of using VCSELs in the pixels as lasers, the temperature range can be set via a "Detuning" of the cavity with respect to the bandgap in the VCSEL, with the same quantum walls in the VCSEL. The resonant wavelength of the cavity can be set via the epitaxial layer thickness of the respective VCSEL. The temperature range can also be set via "detuning" of the cavity with the bandgap, with the resonant wavelength being the same. The band gap can be set via the layer thickness of the quantum walls.

It can be provided that at least two lasers with different temperature operating ranges of the pixels can be operated jointly. Depending on the temperature range, typically only lasers whose current temperature falls within their temperature operating range provide a significant contribution to optical performance. The electronic circuit for actuating the laser in the pixel can be realized relatively easily. Furthermore, no temperature sensor is required.

Alternatively, it can be provided that at least one laser, the current temperature of which lies within its temperature operating range, can be operated as a function of the current temperature. This can be achieved via a correspondingly designed circuit for the laser for actuating the pixels and by using a temperature sensor. The temperature sensor can be arranged in the vicinity of the pixel field or, for example, on the housing of the transmitting device or of the optoelectronic device. The temperature sensor may also be an ambient temperature sensor present in modern motor vehicles.

In order to meet the requirements of a motor vehicle, for example, it can also be provided in an alternative embodiment that a laser, in particular a VCSEL, is arranged in each pixel of the pixel field, said laser having the same temperature operating range, whereas lasers having different temperature operating ranges are arranged in different pixels. For example, lasers, in particular VCSELs, having two different temperature operating ranges can be provided. The first temperature operating range may extend, for example, from-40 ℃ to +40 ℃, while the second temperature operating range may extend, for example, from +40 ℃ to +120 ℃. In each pixel of the pixel field, a laser having a first temperature operating range or alternatively a second temperature operating range may be provided. It is preferred here that the same number of pixels of the pixel field have lasers with a first temperature operating range and with a second temperature operating range.

The invention also relates to an optoelectronic device, in particular for detecting obstacles and/or for measuring distances, comprising:

transmitting device for emitting a laser beam, wherein the transmitting device has a pixel field, wherein each pixel of the pixel field has at least one laser, in particular an optoelectronic laser such as VCSEL, μ VCSEL or VECSEL, wherein the pixels of the pixel field are divided into at least one first pixel group and a second pixel group, wherein each pixel of the first pixel group has at least one optoelectronic laser which is designed for laser operation in a first temperature range, for example between-40 ℃ and +25 ℃, and wherein each pixel of the second pixel group has at least one optoelectronic laser which is designed for laser operation in a second temperature range, for example between 25 ℃ and +90 ℃.

VCSELs or μ VCSELs, also referred to as micro VCSELs, are particularly considered as optoelectronic lasers. VECSEL or μ VECSEL are also contemplated.

The VCSEL-constrained structure may have the following characteristics: due to the lasing mode formed in the resonator arrangement, the emitted wavelength in the laser operation has a significantly smaller shift with respect to temperature in comparison with an edge-emitting laser (EEL). The offset may be determined by the optical path length of a cavity formed between the mirrors of the resonator device in which the active region is disposed. The optical path length is in particular related to the refractive index of the material in the resonator device, which has a small temperature dependence. Due to the small resonator length in a VCSEL or μ VCSEL, the higher longitudinal modes have wavelengths far outside the gain spectrum of the active material. The effective resonator length can be in the range of several wavelengths. The transverse modes can be suppressed by using suitable apertures.

In the wavelength range between 900nm to 950nm, which is of interest for sensor applications, the VCSEL may have a shift in the wavelength of the emission of 0.07 nm/K. Whereas edge-emitting lasers have relatively long cavities, e.g. 300 μm to 3mm cavities, so that the longitudinal modes lie closely within the gain spectrum of the active material. The mode always oscillates with maximum gain if no further measures are taken. The maximum of the gain spectrum essentially shifts with the bandgap of the active material with respect to temperature. This shift is much greater than the temperature dependence of the refractive index. For example, a typical 905nm EEL laser has a wavelength temperature coefficient of 0.28 nm/K.

Due to the above-mentioned properties, edge-emitting lasers have a significantly lower temperature dependence of the optical power on temperature, since their laser mode always oscillates at maximum gain. Whereas in VCSEL or μ VCSEL the wavelength is determined by a short resonator. The gain spectrum shifts with respect to temperature by the resonance preset by the resonator. This results in a strong dependence of the gain and thus of the power on the temperature.

For many sensor applications, ambient light, such as sunlight, plays an important role as a disturbing factor. The signal-to-noise ratio (SNR) may be negatively affected by ambient light, or the sensor may be completely overexposed by ambient light, for example, when the lidar system is "looking" at the sun.

Therefore, long-wavelength filtering may be important on the sensor side. Since the temperature shift of the wavelength is less in a VCSEL or μ VCSEL, such a filter can be designed narrower than in the case of an edge-emitting laser. Exemplary considerations for typical parameters of application in automobiles predict, for example, a bandpass filter width of 10nm for VCSEL sources and 70nm for edge-emitting lasers. This results in a suppression of the solar scattered photons by about one order of magnitude.

In the optoelectronic device described here, which may be designed, for example, as a VCSEL array or as a VCSEL field, a plurality of optoelectronic lasers, in particular in the form of VCSELs, are designed for laser operation in a first temperature range, and a further number of optoelectronic lasers, in particular in the form of VCSELs, are designed for laser operation in a second temperature range. The relatively high temperature dependence of the power of the VCSEL can thereby be compensated by means of the VCSEL field.

The optoelectronic device is particularly suitable for use in motor vehicles, for example in lidar systems, and/or as a transmitter for sensor applications, for example with reduced brightness requirements, which not only have a smaller wavelength shift but also a smaller shift in the optical power with respect to temperature.

The first temperature range is different from the second temperature range. The first and second temperature ranges may then follow one another, wherein no overlap of the temperature ranges may be provided or alternatively a partial overlap of the temperature ranges may be provided.

It can be provided that the respective optoelectronic laser has a resonator device and an active region, wherein the active region is embedded in the resonator device. The resonator device may be formed by a mirror in which the active region is embedded. The mirror may be implemented by a layer of material, for example as a bragg mirror. These mirrors are also known as "distributed bragg reflectors", or simply "DBRs". The mirrors are thin layers of alternating, different refractive index dielectric materials. The active region can be formed in a manner known per se from a layer of semiconductor material and for example has quantum wells or quantum dots.

For a VCSEL designed for laser operation in the first temperature range or the second temperature range, the same emission wavelength can be emitted by the design of the mirror layer and the length of the cavity. However, VCSELs may differ at the same temperature due to the wavelength location of the gain spectrum of the active region. Thus, the VCSEL can be optimized for laser operation in a lower first temperature range, e.g. between-40 ℃ and 25 ℃, and optimized for laser operation in an upper second temperature range, e.g. between 25 ℃ and 90 ℃.

For example, different gain spectra may be achieved by different designs of the active region, for example by using different thicknesses of the quantum wells and/or by different tensions and/or different compositions of the quantum wells.

The resonator means of the optoelectronic laser of the first pixel group and the resonator means of the optoelectronic laser of the second pixel group may be identically or differently designed and/or identically or differently dimensioned. In particular, the mirror layers and the length of the cavities between the mirror layers can be designed at least substantially identically. The region between the mirror layers where the active region is located is called the cavity. Thus, the cavity does not form a cavity between the mirrors, but is filled with a material, in particular an active region.

According to a further development of the invention, the active regions of the optoelectronic lasers of the first group of pixels and the active regions of the optoelectronic lasers of the second group of pixels can be differently designed and/or differently dimensioned, wherein the active regions of the optoelectronic lasers of the first group of pixels are coordinated with the laser operation in the first temperature range, and wherein the active regions of the optoelectronic lasers of the second group of pixels are coordinated with the laser operation in the second temperature range. As already introduced above, at the same temperature, the active regions may differ in wavelength position of the gain spectrum, for example due to differently designed quantum wells.

The optoelectronic lasers of the first group of pixels may originate from a first wafer and the optoelectronic lasers of the second group of pixels may originate from a second wafer. Thus, for example, VCSELs designed for operation in different temperature ranges can be provided in a simple manner in terms of process technology.

It may be provided that the pixel field comprises a plurality of rows or columns with pixels. Only the pixels of the first group of pixels or the pixels of the second group of pixels can be arranged alternately in successive rows or columns, respectively. Alternatively, one pixel of the first and second pixel groups is arranged alternately in each row or in each column, in particular such that a checkerboard arrangement of the pixels of the first and second pixel groups results. The desired arrangement can be formed from the individual VCSELs by means of suitable methods, such as stamping techniques, self-organization or pick and place.

It can be provided that all the optoelectronic lasers of the pixel field are connected in parallel. In the low temperature range, the optoelectronic laser of the first pixel group substantially contributes to the lasing. In contrast, in the higher temperature range, the optoelectronic laser of the second pixel group substantially contributes to the lasing. The disadvantage of this is that the overall efficiency of the VCSEL array is roughly halved, since typically half of the lasers contribute no or only a small contribution to the available laser radiation (50-50 division of the first and second pixel groups). The precise voltage in production is also difficult to control.

The optoelectronic lasers of the first pixel group can be operated electrically separately from the optoelectronic lasers of the second pixel group. This can be achieved in different ways and methods. For example, the substrate on which the VCSEL is applied may have, for example, a silicon-based or CMOS-based chip which already contains a current source, in particular a switching transistor, for each laser.

In other embodiments, the contacts of the optoelectronic laser can only be guided down through vias through the substrate. The feeding of the lines to the drivers is then organized via a PCB (representing a printed circuit board) located below the chip, so that individual manipulation of different groups of pixels can be achieved. In a further embodiment, the optoelectronic lasers are connected to one another on the surface of the carrier substrate by means of busbars. In this case, and in other embodiment variants, all the optoelectronic lasers can be connected in parallel, optionally with their own driver, or partially in parallel and in series, for example in order to reduce the number of connection points and/or to increase the operating voltage and to reduce the total current generated thereby.

The optoelectronic laser may be, in particular, a VCSEL, μ VCSEL, VECSEL or μ VECSEL. If a VCSEL is mentioned here, the corresponding case can also relate to a VCSEL, VECSEL or μ VCSEL.

The optoelectronic device is particularly well suited for applications that are subject to greatly varying ambient temperatures, for example in motor vehicles.

The invention also relates to a lidar system having at least one optoelectronic device according to the invention and an evaluation device for determining the distance to an object reflecting the emitted laser beam on the basis of the laser beam detected by means of the receiving device.

The invention further relates to a method for producing an optoelectronic device, in particular an optoelectronic device according to the invention, wherein in the method a pixel field is formed having a plurality of pixels on a carrier, wherein each pixel has at least one optoelectronic laser, in particular a VCSEL, and wherein in the method an electronic controller for actuating the pixels is provided and/or formed, in particular on the carrier, wherein for actuation purposes the pixels of the pixel field are divided into a plurality of pixel groups, and wherein the controller is designed such that the controller operates the pixel groups at different, successive time intervals.

Drawings

The invention is explained in more detail below by way of example and with reference to the accompanying drawings. The figures are each shown schematically in a single view,

fig. 1 shows a plan view of a transmitting device according to a variant of the optoelectronic device according to the invention;

FIG. 2 shows a top view of the target area of the apparatus of FIG. 1;

FIG. 3 shows a diagram of an optical system for a pixel of a transmitting device of the apparatus of FIG. 1;

fig. 4a shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

FIG. 4b shows a top view of a receiving device for the transmitting device of FIG. 4 a;

FIG. 5a shows another top view of the transmitting device of FIG. 4 a;

FIG. 5b shows another top view of the transmitting device of FIG. 4 b;

fig. 6a shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

FIG. 6b shows a top view of a receiving device for the transmitting device of FIG. 6 a;

fig. 7a shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

FIG. 7b shows a top view of a receiving device for the transmitting device of FIG. 7 a;

fig. 8a shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

FIG. 8b shows a top view of a receiving device for the transmitting device of FIG. 8 a;

fig. 9a shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

fig. 9b shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

fig. 10 shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

fig. 11 shows an electronic circuit of an optoelectronic laser for actuating pixels of a transmitting device according to a variant of the optoelectronic apparatus according to the invention;

fig. 12 shows an alternative electronic circuit for an optoelectronic laser for actuating pixels of a transmitting device according to a variant of the optoelectronic apparatus according to the invention;

fig. 13 shows a cross-sectional view of a transmitting device according to a variant of the optoelectronic apparatus according to the invention;

fig. 14 shows a cross-sectional view of a transmitting device according to a further variant of the optoelectronic apparatus according to the invention;

fig. 15 shows a number of possible designs of the pixels on the carrier;

fig. 16a shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

fig. 16b shows a top view of a transmitting device of a further variant of the optoelectronic device according to the invention;

fig. 17a shows exemplary amplification curves with respect to wavelength for temperatures of-40 ℃, 25 ℃ and 90 ℃ and the emission wavelength preset by the resonator of the VCSEL in the case of a VCSEL optimized for laser operation in the lower first temperature range; and

fig. 17b shows exemplary amplification curves for temperatures of-40 ℃, 25 ℃ and 90 ℃ as a function of the wavelength and the emission wavelength predefined by the resonator of the VCSEL in the case of a VCSEL optimized for laser operation in the higher, second temperature range.

Detailed Description

Fig. 1 shows a plan view of a part of a transmitting device 21 of a variant of the optoelectronic device according to the invention. The transmitting means 21 have a field of pixels 23 which is an array-like arrangement of pixels 25. Some pixels 25 are exemplarily shown and are particularly bounded by dashed lines. Each pixel 25 of the pixel field 23 comprises at least one laser, in particular a VCSEL. The pixel field 23 is divided into a number N of segments 27. The boundaries between the sections 27 are marked by means of dot-dash lines. In the example shown, each segment 27 comprises four pixels 25, respectively, which are arranged in a square arrangement, so that two pixels 25 of a row of the pixel field 23 are assigned to a segment 27 and a segment 27 extends over two rows. However, the subsections shown in FIG. 1 should be taken as examples only.

In the case of the transmission device 21, the pixels 25 are divided into a plurality of pixel groups. In the transmitting device 21 according to fig. 1, four pixel groups are provided, corresponding to the number of pixels 25 per segment. Furthermore, in each section 27, a respective pixel 25 is associated with a respective pixel group. The transmitting means 21 are designed to operate the pixel groups in different successive time intervals.

For example, the pixel 25a located at the upper left of the corresponding section is associated with the first pixel group; the pixel 25b located at the upper right in the section 27 is associated with the second pixel group; pixel 25c, located to the lower left of the respective segment 27, is associated with a third group of pixels; and the pixel 25d located at the lower right in the corresponding section 27 is associated with the fourth pixel group. The four pixel groups are operated in different successive time intervals. Thus, for example, pixel 25a operates during a first time interval while the remaining pixels do not operate. In a subsequent second time interval pixel 25b is active, in another time interval pixel 25c is active, and in yet another time interval pixel 25d is active. This sequence can be repeated in further subsequent time intervals, or the operating sequence of the pixel groups can also be changed, whereby, as already described above, interference problems in the use of optoelectronic devices in lidar systems can be avoided.

The segmentation of the pixel field 23 of the transmitting device 21 and the association of the pixels 25 with the respective pixel groups allows a simultaneous operation of a plurality of pixels, i.e. the pixels of the respective pixel groups. In contrast to the individual, individual activation of each pixel 25 of the pixel field 23, the overall exposure time for image recording can be reduced when used in a lidar system. For example, the pixel field 23 may have 600 × 200 pixels. The laser beam requires about 1 μ s for the outbound and inbound trips over a distance of 150m (2 × 150m corresponds to a light time of flight of 1 μ s). In the case where each individual pixel 25 of the pixel field 23 is activated individually within its own time interval, the total exposure time would be about 120ms (600 × 200 × 1 μ s — 120 ms). By simultaneously activating the pixels 25 of the respective pixel groups, the exposure time may be reduced as described above, as will be explained in more detail below. Another advantage is that due to the segmentation of the pixel field, the illumination may be made differently according to the respective spatial angle, e.g. with respect to wavelength, pulse shape, power, etc.

In the pixel field 23 shown in fig. 1, each pixel 25 may have a cross-sectional area of 40 μm × 40 μm and contain, for example, 1 to 5 VCSELs. For example, the pixel field may also have a width of 24mm and a height of 8mm, such that it comprises a total of 600 × 200 pixels.

The Field-of-Illumination FOI 29 shown in top view in fig. 2 may be located, for example, at a distance of 200m in front of the pixel Field 23 of the transmitting device 21 of fig. 1. The object field 29 can, for example, have a width of 231m and a height of 70.6m, using corresponding projection optics. One pixel 25 is here projected onto an area of about 0.349m × 0.349 m. The size data of the object field 29 is only to be regarded as an example. The aspect ratio of the pixel field, e.g. 24:8, is preferably kept constant in the object field. The size of the pixel field can thus be projected or enlarged into the object field by means of distortion-free projection optics.

The optical system shown in simplified form in fig. 3 comprises at least one lens 31 in front of the respective associated pixel 25. The lenses 31 are preferably arranged in front of the respective pixels 25 at a distance of their focal length. In order to maintain the etendue of the laser radiation emitted by the pixel, according to one example, the lens 31 should have a lens diameter of more than 10.3mm and a focal length of 23mm, in particular also to achieve illumination of the target field, as described with reference to fig. 2. When a collimating lens (not shown) is used in front of the pixels 25, the required diameter of the lens 31 may be reduced, for example to a value larger than 4.12 mm.

The transmitting device 21 shown in a plan view in fig. 4a corresponds substantially to the transmitting device of fig. 1. Shown are four segments 27 of the pixel field 23, wherein each segment 27 in turn has four pixels. Each one pixel 25 of the section 27 is associated with a respective group of pixels. For example, pixel 25a from upper left segment 27a is associated with a first group of pixels; pixel 25b from upper right segment 27b is associated with a first group of pixels; and pixel 25d from the lower left segment 27c is associated with a first group of pixels; and pixel 25c from the lower right segment 27d is associated with the first group of pixels.

As already explained above with reference to fig. 1, the transmitting device 21 according to fig. 4a is designed to operate pixel groups in different successive time intervals. Thus, during a time interval, the pixels associated with the first group of pixels are active and the remaining pixels are inactive.

Fig. 4b shows a top view of the receiving device 33, which comprises a two-dimensional detection field 35 divided into a plurality of detection regions 37. The number of detection regions 37 corresponds to the number of segments of the pixel field 23 according to fig. 4 a. In this case, one detection region 37 is provided for each section 27, so that a detection region 37 is provided for detecting the reflected laser beam originating from the associated section 27. The correlation can also take place, in particular, in a detection unit (not shown) arranged downstream of the receiving device 33, which processes and/or evaluates the signals detected in the respective detection region 37.

For example, detection region 37a may be associated with zone 27a, detection region 37b may be associated with zone 27b, detection region 37c may be associated with zone 27c, and detection region 37d may be associated with zone 27 d. At least one pixel for detecting laser radiation may be provided in each detection region 37. Therefore, the resolution of the receiving apparatus 33 is inferior to that of the transmitting device 21. However, the number of time steps required for image recording and scanning the target field (see fig. 2) is reduced by the number of detection areas. For example, if each pixel is operated in an individual time interval with 600 × 200 pixels in the pixel field 23, a relatively long exposure time results. The exposure time reduces the number of detection regions 37 of the receiving device 33 and can thus be significantly shortened with a corresponding number of detection regions 37.

Fig. 5a shows the transmitting device 21 of fig. 4 a. In this case, the pixels associated with the second group of pixels are operated in a further second time interval. For example, pixel 25b from upper left segment 27a is associated with a second group of pixels; pixel 25d from upper right segment 27b is associated with a second group of pixels; pixel 25c from lower left segment 27c is associated with a second group of pixels; and the pixel 25a from the lower right segment 27d is associated with a second group of pixels. All other pixels not associated with the second group of pixels are not operated during the second time interval. The reflected laser radiation can in turn be detected via the receiving means 33 shown in fig. 5 a. Here, each detection region 37 detects laser radiation from the respective associated section 27.

In the variant of fig. 6a, the pixels in the sections 27a and 27d emit laser beams with a first polarization. For example, the first polarization may be a linear polarization in the horizontal direction H, see detection areas 37a and 37d associated with sections 27a and 27d of detection field 35 of receiving device 33 according to fig. 6 b. In contrast, the pixels 25 of the segments 27b and 27c emit a laser beam with a second polarization, which may be, for example, a linear polarization in the vertical direction V. The respective vertical polarization directions V are indicated in the detection areas 37c and 37 b.

The detection zone 37a associated with the section 27 has a polarizing filter (not shown) that allows the light emitted in the horizontal polarization direction H to pass. Thus, the polarization filter of the detection area 37a is matched to the polarization direction of the laser beam emitted by the segment 27 a. In contrast, the polarization filter of the detection region 37a blocks the laser light having the vertical polarization direction V from the sections 27b and 27 c.

In a corresponding manner, the other detection regions are also equipped with a polarization filter which is matched to the polarization of the laser beam emitted by the respective associated section of the transmitting device. In contrast, the detection regions adjoining the respective detection region via the longitudinal sides have polarization filters which let the light pass in the orthogonal polarization direction.

By using the segments 27a to 27d, if the segments 27 in a row or column of the pixel field 23 are considered, laser light with a horizontal or vertical polarization is always emitted alternately, and by equipping the associated detection regions 37a to 37d with correspondingly matched polarization filters, the scattered light detected in the respective detection regions 37a to 37d, for example originating from laser radiation of the non-associated segments, can be significantly reduced. The detection of other interfering light such as, for example, solar background radiation and radiation from other lidar sources may also be reduced.

In the variant of fig. 7a, the pixel field 23 of the transmitting device 21 is designed such that the pixels of sections directly adjacent to one another in a row or column of the pixel field 23 emit laser beams having different, in particular slightly different, properties. For example, the pixels 25 of the segment 27a may emit a laser beam having a wavelength of at least about 939 nm. The same applies to the pixels 25 of the section 27 d. In contrast, pixels 25 of segments 27b and 27c may emit laser beams having a wavelength of at least about 941 nm. For example, VCSELs emitting different wavelengths may be from different dies. The wavelength data is again only to be seen as an example. According to another example, a wavelength difference of 20nm or 25nm or 30nm or 35nm or 40nm or more may be advantageous. The wavelengths may also differ considerably from each other. For example, the first wavelength may be at least about 850nm and the second wavelength may be at least about 905nm or 1600 nm.

As shown in fig. 7b, the detection regions 37a to 37d associated with the respective sections 27a to 27d have appropriately configured spectral filters matched to the wavelength of the laser beam. For example, the detection region 37a has a spectral filter, for example a band-pass filter, through which the laser beams emitted by the associated section 27a at 939nm can pass, so that these laser beams can be detected by the section 37 a. In contrast, the spectral filter blocks light of other wavelengths, and in particular at 941 nm. Therefore, the laser beams emitted by the sections 27b and 27c cannot be detected by the detection field 37 a. Thus, detection of undesired scattered light may be reduced.

The remaining detection regions 37b to 37d are equipped with respective filters matched to the wavelength of the associated section 27b to 27 d.

In the variant according to fig. 8a, the segments 27a to 27d adjoining one another in a row or column of the pixel field 23 emit laser beams with different polarization directions. In particular, one segment emits a laser beam with a horizontal polarization direction H, while a segment adjacent to this segment in a row or column emits a laser beam with a vertical polarization direction V (see the polarization directions in the detection regions 37a to 37d of the detection field 35 of the receiving device 33 according to fig. 8 b). For example, the pixels of segment 27a emit a laser beam with a horizontal polarization direction H, while the pixels of segment 27b located beside segment 27a in the row of pixel field 23 emit a laser beam with a vertical polarization direction V. The section 27c located below the section 27a in the same column of the pixel field 23 likewise emits a laser beam with a vertical polarization direction V. While the immediately adjacent section 27d in the same row emits a laser beam with a horizontal polarization direction H.

The detection areas 37a to 37d of the detection area 35 of the receiving means 33 are equipped with respective polarization filters, so that the detection areas 37a and 37d can detect laser beams having a horizontal polarization direction H and so that the detection areas 37b and 37c can detect laser beams having a vertical polarization direction V.

In the variant of fig. 8a, the section is also divided into subsections. Each section is preferably divided into two subsections, with the same number of pixels being associated with each subsection. The subsections differ in that they emit light of different wavelengths. For example, section 27a is divided into subsections 39a and 39 b. Subsection 39a includes pixels 25a and 25c and subsection 39b includes pixels 25b and 25d of section 27 a. In a corresponding manner, the sections 27b, 27c and 27d are divided into two sub-sections 39a and 39b, respectively, which emit light of different wavelengths. The pixels 25a and 25c associated with sub-segment 39a emit light with a wavelength of 939nm, for example, while the pixels 25b and 25d associated with sub-segment 39b emit light with a wavelength of 941 nm. It is noted that the arrangement of the sections 39a and 39b may vary from section to section. Therefore, pixels capable of emitting light of one wavelength can be set differently in different regions from segment to segment.

In the receiving device 33 according to fig. 8a, each detection region 37a to 37d is divided into two sub-regions 41a and 41b which are associated with the respective sub-section 39a or 39b and have a respective matched spectral filter in order to allow light from the associated sub-section to pass and to block light from the respective non-associated sub-section.

In the variant according to fig. 8a and 8b, the detection of scattered light in the individual detection regions 37 can be further reduced by the measures described above, in particular by using and detecting laser beams having different wavelengths and different polarizations.

With reference to fig. 9a, a variant of the optoelectronic device according to the invention is described in which the pixel field 23 of the transmitting means 21 has a plurality of pixels 25, which are separated from one another by the lines drawn with dashed lines in fig. 8 a. Each pixel 25 has a plurality of optoelectronic lasers, which are preferably VCSELs. The VCSELs of each pixel 25 are subdivided into two groups of VCSELs which differ in their temperature operating range.

As shown in fig. 9a for the pixel 25 located at the upper left, said pixel has a first set of VCSELs 43a, the temperature operating range of which is for example in the range-40 ℃ to +40 ℃. In addition, the pixel 25 has a second set of VCSELs 43b, which operate at a temperature in the range between +40 ℃ and +120 ℃, for example. The other pixels 25 of the pixel field 23 are provided with a respective first set of VCSELs and a respective second set of VCSELs. Each pixel 25 of the pixel field 23 thus has a VCSEL which allows operation of the laser in the temperature range-40 ℃ to +120 ℃ as required in automotive requirements. The pixel field 23 of the transmitting device 21 according to fig. 9a is therefore particularly suitable for use in automotive applications.

In the variant of fig. 9b, each pixel 25 likewise has a first group of VCSELs 43a and a second group of VCSELs 43 b. Two VCSELs 43a and one VCSEL43b are provided here. This is only to be seen as an example, and in particular also conversely, one VCSEL43a and two VCSELs 43b may be provided. As shown in fig. 9b, the VCSELs 43a and 43b are arranged slightly offset with respect to the centerline of the column.

In the variant of fig. 10, lasers with different temperature operating ranges are arranged pixel by pixel 25. The pixel 25a located at the upper left has, for example, only the VCSEL43a in the first group of VCSELs 43a, while the adjacent pixel has only the VCSEL43b in the second group of VCSELs 43 b. In particular, the first set of VCSELs 43a or the second set of VCSELs 43b may be arranged alternately pixel by pixel in each row of the pixel field 23. The same applies for each column of the pixel field. Thus, the first set of VCSELs 43a or the second set of VCSELs 43b, respectively, may be alternately arranged pixel by pixel in each column of the pixel field 23. Manufacturing is thereby simplified because the VCSEL of the same structure is provided in each pixel.

Fig. 11 shows an electronic circuit for manipulating the VCSELs 43a, 43b of the pixel 25. As shown, the VCSELs 43a, 43b of the first and second sets of VCSELs are connected in series. A common, simultaneous manipulation of the VCSELs 43a, 43b of the pixels 25 thus takes place. In this case, the current through the VCSELs 43a, 43b is switched on or off by means of the transistor 45 in order to operate or not operate the VCSELs. Depending on the temperature range, the VCSELs of the first group of VCSELs 43a or the VCSELs of the second group of VCSELs 43b are in the optimum operating range, while the other group of VCSELs does not contribute or only slightly contributes to the emission spectrum. The simultaneous emission of the first and second group of VCSELs 43a and 43b, for example in the transition region between the temperature operating ranges of the two VCSEL groups at 40 ℃, is furthermore problem-free. The circuit according to fig. 11 is easy to implement and works without a temperature sensor.

Fig. 12 shows an electronic circuit for individually manipulating the VCSELs of the first set of VCSELs 43a and the VCSELs of the second set of VCSELs 43 b. As shown in fig. 12, each group of VCSELs is arranged in its own row, which runs parallel to each other. Depending on the temperature measured by means of the temperature sensor 51, the transistor 47 or the transistor 49 is loaded to operate the VCSEL43a of the first group of VCSELs or the VCSEL43b of the second group of VCSELs. The temperature sensor 51 may be an ambient temperature sensor, such as is commonly already present in modern motor vehicles.

Fig. 13 shows the region of the transmitting device 21 in cross section, wherein the pixel field 23 has a carrier 53 on which the array-like pixels 25 each having at least one VCSEL55 are arranged. The carrier 53 may have at least one integrated circuit, for example a silicon-based integrated circuit, for handling the VCSEL 55. The circuit may have logic elements and driver elements, for example transistors, in order to be able to operate the VCSEL55, for example, in a pulsed operating mode. The carrier 23 may in particular be a so-called silicon backplane.

The VCSEL55 can be arranged on the carrier 23, in particular as a μ VCSEL (micro-scale VCSEL), by means of parallel chip transfer. Alternatively, the VCSEL55 may be "bonded" directly onto the carrier 53 as a wafer by means of wafer bonding.

In the embodiment of fig. 14, the carrier 53 is formed passively. A controller 57 is associated with each pixel 25, which is arranged on the carrier 23 and by means of which the operation of the VCSEL55 of the pixel 25 takes place. Alternatively, it can also be provided that a plurality of pixels 25 are associated with the controller 57.

The VCSEL55, in particular as a μ VCSEL, and the controller 57 may be arranged on the passive carrier 23 by means of parallel chip transfer. The controller 57 may be configured as an integrated circuit.

Fig. 15 serves to illustrate different possibilities for arranging the VCSEL on the carrier 53. For example, the VCSEL55, in particular as a μ VCSEL, may be provided on the carrier 53 without a substrate. In a variant, the VCSEL55 can be arranged on the carrier 53 by means of an auxiliary substrate 59. For example, the auxiliary substrate may be created, for example, by "rebonding" the VCSEL wafer onto a Si, Ge, SiC, or sapphire substrate, and then removing the original growth substrate.

In a further variant, the VCSEL55 can be arranged on the carrier 53 in a so-called back-side arrangement. For example, the substrate 61 above the VCSEL55 may be composed of GaAs. Light may be coupled out through the GaAs substrate at, for example, 940 nm.

In a further variant, a lens 63, for example for beam collimation, can be formed on the upper side of the substrate 61, for example made of GaAs.

In a further variant, the VCSEL55 can be arranged on the carrier 53 by means of a substrate 65 (for example GaAs). The substrate 65 is located between the carrier 53 and the VCSEL 55.

In the optoelectronic device described above, the transmission devices 21 are designed to emit a laser beam, wherein the respective transmission device 21 has a field 23 of pixels 25 and each pixel 25 of the pixel field 23 has at least one laser, in particular a VCSEL. The receiving device 33 is also provided for detecting the laser beam, in particular the laser beam reflected back at the object. The pixels 25 of the pixel field 23 can be divided into a plurality of pixel groups, and the respective transmission means 21 are designed to operate the pixel groups in different successive time intervals.

The top view of the transmitting means 21 of the variant of the optoelectronic device according to the invention shown in fig. 16a comprises a pixel field 23. Each pixel 25 of the pixel field 23 comprises an optoelectronic laser 25 in the form of a VCSEL. Alternatively, the optoelectronic laser may be a respective μ VCSEL, VECSEL or μ VECSEL.

The pixels 25 of the pixel field 23 are divided into at least a first pixel group 67 and a second pixel group 69, wherein in the example of fig. 16a the pixels 67, 69 are arranged in a checkerboard pattern.

Each pixel in the first pixel group 67 here comprises a VCSEL which is designed for laser operation in a first low temperature range (LT for "low temperature"), for example between-40 ℃ and +25 ℃. In contrast, each pixel of the second pixel group 69 comprises at least one VCSEL designed for laser operation in a second, higher temperature range (HT for "high temperature"), for example between 25 ℃ and +90 ℃.

In contrast to the variant according to fig. 16a, in the transmitting device 21 shown in top view in fig. 16b, the pixels 25 of the first and second pixel groups 67, 69 are arranged in different columns of the pixel field 23.

The checkerboard or column-like arrangement of the first and second pixel groups 67, 69 shown in fig. 16a, 16b in the respective pixel field 23 is only to be seen as an example. Other arrangements of the first and second pixel groups 67, 69 are also possible. It is also possible to assign half of the pixels to the pixels of the first pixel group 67 and the other half to the pixels of the second pixel group 69. Other divisions are also possible.

Since the VCSELs of the first pixel group 67 are designed for laser operation in a first, low temperature range and the VCSELs of the second pixel group 69 are designed for laser operation in a second, higher temperature range, the optoelectronic device with a transmitting device according to fig. 16a or 16b is suitable for applications in which the ambient temperature varies greatly, for example in a laser radar system of a vehicle.

The first and second temperature ranges may partially overlap each other or directly adjoin each other, in particular not overlap.

For the electrical actuation of the VCSELs, it can be provided that the VCSELs of the first and second pixel groups 67, 69 are connected in parallel. Thereby, all VCSELs can be operated simultaneously. At low temperatures, the VCSELs of the first pixel group 67 then at least substantially contribute to the laser emission. In contrast, in the higher temperature range, the VCSELs of the second pixel group 69 at least substantially contribute to the laser emission.

Alternatively, the VCSELs of the first pixel group 67 can be operated separately from the VCSELs of the second pixel group 69. This can be achieved, for example, by the substrate on which the VCSEL is applied having a chip, for example a silicon-or CMOS-based chip, which contains a current source, in particular a switching transistor, for each optoelectronic laser. In this way, separate operation of the different pixel groups can be achieved by corresponding activation of the switching transistors. Other possibilities of individual manipulation of the pixel groups are also conceivable.

The VCSELs of first pixel group 67 and second pixel group 69 may originate from different wafers. The wafer can be designed such that the VCSELs on the wafer have at least substantially the same emission wavelength λ due to the design of their mirror layers and the length of the cavity between the mirror layers provided with the active region_res. However, the VCSELs of the two wafers may differ in that the wavelength positions of the gain spectra are different at the same temperature, as shown in fig. 17a and 17b according to the gain curves at-40 ℃, 25 ℃ and 90 ℃. Thus, the VCSELs of one wafer are optimized for laser operation in a lower first temperature range, as shown in fig. 17a, while the VCSELs of the other wafer are optimized for laser operation in an upper second temperature range, as shown in fig. 17 b.

Optimization of the temperature range between the lower temperature (e.g., -40 ℃) and the upper temperature (e.g., +25 ℃) can be achieved by the emission wavelength λ_resAt least approximately through the intersection of the gain curve with respect to the lower temperature and the upper temperature, as shown in fig. 17a and 17 b.

List of reference numerals

21 transmitting device

23 field of pixels

25. 25a-25d pixel

27. 27a-27d section

29 destination Field (Lighting Field, Field of Illumination FOI)

31 lens

33 receiving device

35 field of detection

37. 37a-37d detection area

39a, 39b sub-sections

41a, 41b sub-regions

43a first group of VCSELs

43b second group VCSEL

45 transistor

47 transistor

49 transistor

51 temperature sensor

53 vectors

55 VCSEL

57 controller

59 auxiliary substrate

61 substrate

63 lens

65 substrate

67 first group VCSEL

69 second group VCSEL

H horizontal direction

V vertical direction

λ_resEmission wavelength